Custom reports disappear after adding account to Billing Conductor group - Bug?

For new accounts, we deploy custom usage report using AWS CDK. Recently we started looking into Billing Conductor to manage and keep track of billing.

The issue is that when we add account that already had custom usage report created into existing Billing Conductor group, the custom usage report that we created in this account, will disappear...

As far as I can tell, there is no documentation of such thing happening, and no warning stating this is expected behavior....

Furthermore, even though the custom report disappears from the account, we are not able to recreate the report, as it says the report with name is already used. Even if we destroy the CDK that deployed this report, and then try to redeploy it, it will say that the report is already taken. So report is gone, but not really..

9:28:53 AM | CREATE_FAILED | AWS::CUR::ReportDefinition | xxxcostandusagereporthourly Resource handler returned message: "Resource of type 'AWS::CUR::ReportDefinition' with identifier 'xxx-cost-and-usage-report-hourly' already exists." (RequestToken: 2ad00a17-d6e8-486e-b31b-dd1e24a37c86, HandlerErrorCode: AlreadyExists)

So my questions are:

1. This looks like a bug, where enabling Billing Conductor will make your existing custom reports disappear. Can anyone confirm?
2. If it is a "feature" it should be documented. Follow up question is how do we remove the report that does not exist, but somehow exists so we can recreate it with the same name?